I'd call it a backlash thing.
For the longest time leading up to and immediately after the PSP launch, the Sony fanboys were in absolute full force pimping the system as a complete godsend, set to topply Nintendo's handheld empire in a day. They exuded such arrogance and hyped up such unrealistic expectations that to say anything pro-DS was immediately condescended upon as anti-progress in gaming, because the system wasn't as sexy, multi-purpose, or (and most importantly) technicaly powerful.
But then the DS started kicking ass and taking names the day Nintendogs came out in Japan, and ever since the DS fans have been unleashing all of their repressed anger at the pro-PSP crowd, for everything from the PSP's pretty laughable lineup to the DS's absolutely fuckton incredible one. It's the closest thing to a coup you could ever recognize on a gaming forum... people slammed the DS so hard before the PSP was even out that the other camp is being all the more snide while the DS has its day in the sun.
I think it's pretty humorous. But then, I'm one of the ones who plays my DS daily, while my PSP has been redubbed as my portable Family Guy player.